Intense Pulsed Light Conversion of Anatase to Rutile TiO2 for Hybrid TiO2-SnO2/MWCNTs/PVB Room Temperature VOCs Sensor

Volatile organic compounds (VOCs) are toxic air pollutants that require cost effective and accurate sensors for environmental monitoring. A VOCs sensing device was fabricated by spin coating low quantities of TiO2-SnO2 loaded multi-walled carbon nanotubes (MWCNTs) with a polyvinyl butyral (PVB) support matrix onto a quartz crystal microbalance (QCM). TiO2 was partially converted from anatase to rutile phase using rapid microwave and the intense pulsed light (IPL) techniques. Microwave facilitated the drying of the solution and crystal growth while IPI, enabled the conversion of TiO2 from anatase to rutile. The sensing properties were investigated with different VOCs, including ethanol, methanol, isopropanol, and toluene, at different concentrations. The anatase and rutile hybrid TiO2-SnO2/MWCNTs/PVB sensing composite film showed an average of 8.8 times higher responses to VOCs compared with pure anatase TiO2-SnO2/MWCNTs/PVB composite film prepared without IPL. The hybrid sensors exhibited negative motional resistance responses to VOCs and positive motional resistance responses to non-VOCs. The hybrid nanocomposite film also showed good stability at room temperature and the highest response towards ethanol with a limit of detection of 1 ppm.